The present invention relates to an electromagnetic valve which is capable of controlling the fluid flow in dual mode, i.e. a small amount of fluid at one time and a large amount of fluid at the other time, in response to the electric signals applied. In particular, the electromagnetic valve of the present invention is useful in controlling the amount of auxiliary air to be supplied to automobile engines.
The conventional electromagnetic valve of a single coil and a single moving core type can only open or close the fluid passage according to the electric signal, or continuously change the cross-sectional areas of the fluid passage in accordance with the electric signal applied. In other words, there was no single electromagnetic valve that could control the fluid passage in dual mode. In the past, to control the fluid passage in dual step two independent electromagnetic valves were provided as shown for example in the Japanese laid-open patent application No. 57-65834. The arrangement however needs two coils, two moving cores and the like, resulting in an expensive device.